The first thing that strikes you, when the re-formed Specials take to the stage after more than a quarter of a century, is how good they look. They are all in their fifties, all of them fathers, and the last time they all played together was 28 years ago. Yet there are no bald patches or paunches, and they race around as if they’re in training for a sprint race. Apart, of course, from Terry Hall, who stands stock still, surveying the crowd with the baleful look of old, spitting sarcasm from a slightly baggier frame.

The second thing is how fresh and joyful their music sounds — and how vital and relevant their songs’ sociopolitical sentiments, chronicling life amid the racial, economic and class divisions of late-1970s Britain, remain in 2009. Formed in Coventry during the last economic recession to drive a failed Labour government out of power, they blended ska, punk and politics, proving an instant hit with a generation fired up by the Sex Pistols and the Clash.

Between 1979 and 1981, the Specials enjoyed seven Top 10 hits, including the chart-toppers Ghost Town and Too Much Too Young — a song that seemed doomed to become their epitaph when they broke up.

While Hall went on to have a successful subsequent career, with Fun Boy Three, the Colourfield and Vegas, followed by collaborations with everyone from Tricky to Gorillaz, the others have fared less well. Three of them abandoned music careers entirely. Now, after six years of delicate diplomatic talks begun by the guitarist Lynval Golding, they are back together to mark the 30th anniversary of their landmark debut album.

Judging by the numerous times various members spontaneously get up to hug each other as they meet in a London hotel, before a pre-Glastonbury warm-up gig at the tiny 100 Club, they are loving every minute. That was far from the case in 1981, when simmering tensions came to a head and they broke up, acrimoniously, in the dressing room of Top of the Pops, as Britain’s inner cities burnt in race riots to the soundtrack of Ghost Town at the top of the charts. “I’ve had nightmares about it since the 1980s,” admits the traumatised guitarist Roddy Byers, once known as Roddy Radiation. “And I still do.” Horace Panter, the dapper and articulate bass player formerly dubbed Sir Horace Gentleman, sums it up. “We just burnt ourselves out. Too much too young.”

Both men still live in Coventry with their families, and both were apprehensive when they learnt of plans to put the Specials back together. Byers says: “I just thought, ‘Do I want to go through the nightmare again?’” Panter had a new career as an art teacher at a special-needs school (“The job my parents always wanted me to do,” he notes drily) and was not immediately convinced about the reunion. “I had to sit down and think about it,” he confesses.

The band who boasted that they “don’t wanna be rich, don’t wanna be famous” might have had the fame, but they missed out on the fortune. “Someone made some money,” scowls MC Neville Staple, “but we didn’t.” Then again, as Panter points out: “We never made much money first time around, but that was never the object. It was just to be in a group.” Byers recalls the band members being offered £30 a week each by the Clash’s manager, Bernie Rhodes, who took them under his wing in the early days — and was rewarded by being ridiculed in their debut single, Gangsters. “And we were just delighted to be paid to do what we loved doing.”

Yet even that palled eventually. “I used to love it, but it became a chore,” says Staple, openly admitting that he’s doing it for the money now. “I’m not gonna lie, it’ll help me grandkids,” he says. “I’m enjoying it, but, basically, I’m getting the financial reward I didn’t get as a kid.”

There may be a financial incentive, but there is a unity to these six middle-aged men, not just in their on-stage chemistry, but in their offstage banter. The truth is, they are enjoying it more than they once did.

The drummer, John “Brad” Bradbury, who battled serious illness five years ago, talks of the reunion’s “healing” benefits for himself. “I feel so lucky. I’m so excited, I still don’t sleep at night. I woke up at 3am today and couldn’t get back to sleep.” He adds: “I have been humbled by the plaudits people have bestowed on us. There is a passion, and when we look out at that audience...”

There is also a feeling that they know how to cope this time. “We realise the mistakes we made last time,” Panter admits. “We won’t spend time cooped up on a hot bus. We’ll travel independently. We’re not a gang: I don’t go out for a drink with Roddy or talk politics with Lynval or football with Terry. I’ve got a family and my own social life. We make sense when we’re all standing on a stage together.”

So, do they have any happy memories of their times in the Specials Mk 1? “When it was good, it was great,” Panter quips. “But when it was bad, it was horrid.” Byers believes it was America that destroyed the band: “We went straight there after a European tour and on the tour bus, we gradually got to hate each other.”

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